1. Field of the Invention
The invention relates to a photoelectric conversion device for converting an optical signal into an electric signal and then outputting it, or for converting an electric signal into an optical signal and then outputting it.
2. Description of the Related Art
FIG. 4 shows the construction of a conventional photoelectric conversion device.
As shown in FIG. 4, the conventional photoelectric conversion device 41 is constructed such that an optical waveguide 44 optically coupled to an optical fiber 43 is formed on a substrate 42, and an optical device 45 composed of a surface light-emitting element or a surface light-receiving element is mounted on the optical waveguide 44 as well as an IC 46 for driving the optical device 45 or for amplifying an electric signal from the optical device 45. The optical device 45 is electrically connected to the IC 46 via a non-illustrated electric wiring which is formed on the optical waveguide 44.
In the photoelectric conversion device 41, an optical path of the optical waveguide 44 which is optically coupled to the optical fiber 43 is parallel to the substrate 42, while an optical path of the light emitted or received by the optical device 45 is perpendicular to the substrate 42. Therefore, a mirror 47 inclined 45° with respect to a core 44a is formed in the optical waveguide 44 and the optical path is changed by 90° at the mirror 47 to allow the optical coupling of the optical device 45 to the optical waveguide 44.
However, in the conventional photoelectric conversion device 41 described above, the optical fiber 43 is optically coupled to the optical device 45 via the optical waveguide 44 and it is necessary to further form the mirror 47 in the optical waveguide 44 by dicing, etc., thus, there is a problem that it takes time and labor for manufacturing and the manufacturing cost increases.
In addition, the photoelectric conversion device 41 has a problem that the optical loss occurs at two points, which are at a connecting portion between the optical fiber 43 and the optical waveguide 44 and at the mirror 47, and the optical loss occurred is thus large.
Furthermore, in the photoelectric conversion device 41, it is necessary to keep a certain distance at an optical fiber mounting portion in order to impart strength to the optical fiber whose coating is removed. In addition, since it is a structure in which the optical waveguide 44 is formed on the substrate 42 and the entire size of the device is large, further downsizing has been demanded.
To solve the above problems, JP-B-3729240 and JP-A-4-333806 have proposed photoelectric conversion devices that the optical waveguide is removed and an optical device is mounted on a tip of an optical fiber.
In detail, JP-B-3729240 proposes the photoelectric conversion device that a supporting member with an end face substantially flush with an end face of the optical fiber is formed on the periphery of an end portion of the optical fiber, a conductive layer is formed on the end face of the supporting member, and an optical device is mounted on the conductive layer to stride over the optical fiber such that a light emitting portion (or a light receiving portion) of the optical device is opposite to a core of the optical fiber to allow the optical coupling of the optical device to the optical fiber.
JP-A-4-333806 proposes the photoelectric conversion device that a ferrule is provided on an outer periphery of an optical fiber, an end face of the ferrule is matched to an end face of the optical fiber, and the optical device is mounted on the ferrule to stride over the optical fiber such that a light emitting portion (or a light receiving portion) of the optical device is opposite to a core of the optical fiber to allow the optical coupling of the optical device to the optical fiber.